1. Field of the Invention
The present invention relates to a woven slide fastener formed by weaving a coil-shaped element row formed of monofilament made of synthetic resin along one longitudinal edge portion of a fastener tape simultaneously with weaving of the fastener tape, and particularly to a woven slide fastener wherein the coil-shaped element row is not displaced in a width direction of the fastener tape and a stable anchoring form can be obtained.
In this specification, the term "coil-shaped element row" refers to an entire group including a large number of element units wherein each element unit has an upper leg portion and a lower leg portion extending substantially in parallel to each other respectively from upper and lower end portions of a coupling head and the upper and lower leg portions of the adjacent element units are successively connected to each other substantially in a U shape through a connecting portion. In the specification, the element unit is simply referred to as "element".
2. Description of the Related Art
A fastener element row formed by weft inserting by double pick monofilament made of synthetic resin and for constituting the coil-shaped fastener element row on one longitudinal edge portion of a fastener tape simultaneously with weaving of the fastener tape and by forming the monofilament into shapes of elements at the time of the weft inserting is integrated with the fastener tape by using a plurality of element anchoring warps which pass over upper leg portions of the respective elements and are woven into a foundation structure under lower leg portions of adjacent elements while interlacing with wefts. For such a woven slide fastener wherein the fastener element row is woven into and anchored to the fastener tape, there are conventionally many kinds of weaving structures of the anchoring warps. Two kinds of conventional representative weaving structures comprising element anchoring warps and fastener tape foundation structure which is partially applicable to the present invention will be described, but it will be understood that the weaving structure is not limited to the ones described here.
According to Japanese Patent Publication No. 2-17161, a fastener element row formed by weft inserting monofilament made of synthetic resin by double pick as constituting material of the fastener element row on one longitudinal edge portion of a fastener tape simultaneously with weft insertion in ground structure at the time of weaving of the fastener tape and by weaving the monofilament into the fastener tape while forming the monofilament into shapes of fastener elements is anchored and integrated by a plurality of element anchoring warps disposed over upper leg portions of respective elements. In this weaving structure, wefts constituting the foundation structure of the fastener tape are on a lower side of lower leg portions of the respective elements of the fastener element row and the element anchoring warps disposed to pass over the upper leg portions of the respective elements simply interlace mainly with the wefts disposed under the lower leg portions of the adjacent elements.
Also in a weaving structure as disclosed in Japanese Patent Publication No. 63-53802 or Japanese Utility Model Publication No. 7-31687, for example, similarly to the above structure disclosed in Japanese Patent Publication No. 2-17161, a fastener element row formed by weft inserting by double pick monofilament made of synthetic resin as constituting material of the fastener element row on one longitudinal edge portion of a fastener tape simultaneously with weft inserting of ground structure at the time of weaving of the fastener tape and by weaving the monofilament into the fastener tape while forming the monofilament into shapes of fastener elements is anchored and integrated by a plurality of element anchoring warps disposed over upper leg portions of respective elements. According to Japanese Patent Publication No. 63-53802 or Japanese Utility Model Publication No. 7-31687, however, the wefts which are constituting yarns of the fastener tape are weft inserted not only under lower leg portions of respective elements but also over the plurality of element anchoring warps running over the upper leg portions of the respective elements between adjacent two elements so as to form the foundation structure, and the element anchoring warps are wrung upward and downward by the wefts between the respective elements.
According to the weaving structure for anchoring the fastener element row as disclosed in the above Japanese Patent Publication No. 2-17161, however, the element anchoring warp disposed over the upper leg portions of the respective elements of the fastener element row is liable to be displaced in a lateral width direction of the fastener on the upper side of the element upper leg portions. Particularly, the element anchoring warps disposed over the respective element upper leg portions and near the coupling heads are liable to fall off the coupling heads. As a result, a posture of the fastener element row anchored to the fastener tape by weaving becomes unstable and a coupling split occurs in use of the slide fastener, which impairs the functioning of the slide fastener.
According to the weaving structure for anchoring the fastener element row as disclosed in the above Japanese Patent Publication No. 63-53802 or Japanese Utility Model Publication No. 7-31687, on the other hand, as compared with the above weaving structure, the displacements of the element anchoring warps disposed over the upper leg portions of the respective elements in the width direction of the fastener tape are prevented on the upper side of the upper leg portions of the elements and the anchored posture by weaving would be stable. However, the weaving structures of both the warps and wefts are made compact due to tightening of the wefts and a product is liable to lack flexibility.
In coupling of the opposed fastener element rows by the sliding movement of the slider, as shown in FIG. 6, a space between adjacent two coupling heads is necessary to be opened up temporarily in the slider S so as to receive an opposite coupling head. In the weaving structure for anchoring the fastener element row as disclosed in the above Japanese Patent Publication No. 63-53802 or Japanese Utility Model Publication No. 7-31687, such an opening up of the space between the coupling heads is not easy, the coupling is not smoothly carried out, and the slider is difficult to slide. Furthermore, because double-picked weft inserting of the wefts is carried out not only under the lower leg portions of the respective elements of the fastener element row but also between the adjacent two elements, a number of picks is doubled as compared with a normal number of picks. Therefore, increasing manufacturing speed is difficult and productivity is low.